The Process West range billet manifolds is a no holds barred manifestation of what is possible under the hood of a WRX/STI when perfect aesthetics meet high end performance. What you see here is the result of years of research and testing, multiple prototypes and a ground up redesign of the original ground breaking "Corsa Veloce" product range. Available in two major configurations they feature a full billet plenum with generous billet bell mouths and thick wall polished CNC mandrel bent tube components. High end TIG welding assembly makes them suitable for up to 100psi boosted applications. No other product comes close to this level of strength and detail. The range is modular to suit everything from MY99 GC8 to the latest WRX and STI's with any stock throttle or that to suit the 3" Hypertune billet throttle. Custom throttle flanges are available on special request.

Street Version (Compatible with AC)

The plenum volume and runner length combination has been selected for aggressive low and mid range torque while opening up power higher in the rev range. The plenum volume is large enough for serious gains but is still compatible with factory AC. The Street version is suitable for any level of performance modification as we have conducted tests on completely stock engine/turbo/fuel system setups with approximately 9% gains in torque and power level, with the same percentage gain on highly modified setups running E85. For a fully streetable but aggressive setup while retaining the comfort of AC, the Street version manifold is the solution. For cars requiring more power in the upper rev range the street version can be supplied with shorter billet TGV's (lower runner section).

Track Version (Reverse Mount)

This is the pinnacle of induction systems for the Subaru WRX/STI range. The plenum volume and runner length combination has been optimized for brutal low and mid range torque while increasing top end power aggressively. We've had customers pull off other aftermarket intake manifold systems to install this as performance is unmatched. Gains on even a stock setup are quite high at 10%+ however we recommend the Track version manifold for any performance setup not requiring AC up to the most extreme track and drag cars. For cars requiring even more power in the upper rev range the track version can be supplied with shorter billet TGV's (lower runner section).

Billet TGV's (Lower Runner Section)

With the port profile machined to suit ported heads these are a simple upgrade to maximise airflow in all conditions. Available in two lengths, 79mm and 67mm, the shorter of which is required to fit a Process West billet plenum to a GC8. The upper flange surface is O-ringed for a perfect seal to either a stock or aftermarket plenum. Fuel injector ports are machined in such a way that either 11mm or 13mm diameter injectors will seat without needing any adaptors, just use the supplied Viton O-rings as required. Fuel rail mounting points are the same as stock, so it is possible to use this with other aftermarket fuel rails.

Billet Fuel Rails

Unlike anything else on the market these fuel rails are proper "machined from the solid" billet rails, not some cheap machined extrusion pretending to be billet. With accommodation for massive "-8" fittings, these fuel rails will easily cope with large capacity fuel systems using new generation large capacity fuel injectors. The twin top and single end entry/exits are designed to be configured as required. They are available to suit 11mm or 13mm diameter injectors, come supplied with two -8 plugs and mounting hardware to bolt up to either stock, or Process West Billet TGV's.